Gonorrhea is a sexually transmitted disease caused by Neisseria gonorrhoeae. Although the pathogenesis of gonococcal infection is complex, previous study using human volunteers showed that surface-exposed pili are essential for the initiation of gonococcal infection. In general, surface-exposed, antigenic molecules required for virulence make ideal candidates for therapeutic intervention, however, the ability of gonococci to alter the antigenic nature of its pili has hampered such efforts. The goal of this project is to explore the molecular mechanism responsible for the variation of pili. A molecular understanding of this process may aid in the development of novel targets for future therapeutic intervention.